Pipe Fittings

Reducing flanges are sized according to the NPS of the flange and the O.D. of the fitting it attaches to. 

The chemistry makeup of malleable iron is predominantly iron with carbon and silica as major additives. The applicable material specification is ASTM A197, Cupola Malleable Iron with a tensile strength of 40,000 psi, yield strength of 30,000 psi, and 5% elongation. Malleable is more appropriately used in gas distribution systems. Requires annealing.

The material specification for cast (gray) iron is ASTM A126. A typical chemistry is predominantly iron with carbon and silicon as major additives, both higher in percentage than in malleable iron. The higher carbon content is what makes cast iron more brittle. It has a tensile strength of 21,000 psi and there is no appreciable elongation. Cast iron fittings are typically utilized in sprikler and drainage systems. 

Often a Brass-to-Iron union works well in many situations. As the iron fitting is attached, the softer brass insert conforms tightly to the iron, making a strong union. However, in many instances brass seated unions cannot be satisfactorily used on lines where the liquid to be carried has an injurious effect on the brass insert. That is where Iron Seat Unions can be used. Pressure ratings and dimensions remain the same for both. 

Malleable 150 class fittings do not have marking requirements to show that they are 150 class. It is assumed that if unmarked that they are the lowest class. Malleable 300 class fittings are required to be marked as 300 MI and typically have the AAR marking on them. Malleable 300 class fittings are dimensionally different than 150 class fittings.

Yes. Applicable agency registrations include FM (Factory Mutual), UL/C (Underwriters Laboratories/Canada), and have Canadian Registration numbers for use in and up to nuclear applications in Canada. Ward also has NSF certification and applicable fittings can be found on the NSF website. 

The convention for numbering in the U.S. is run x run x outlet. When both runs are the same, the run diameter is only detailed once. For example, a black malleable tee that has both runs at 1 inch and an outlet at ¾ inch would be called a 1 inch x ¾ inch black malleable tee.

When all openings are different, the tee is identified using the largest diameter run first, the 2nd run second and the outlet third. For example, if we had a malleable tee with a 1” run, a ¾” run, and a ½” outlet, it would be called a 1” x ¾” x ½” malleable tee.

For working pressure ratings on cast iron class 125 and class 250 pipe fittings, reference our cast iron threaded fittings spec sheet. For working pressure ratings on malleable iron class 150 and class 300 pipe fittings, reference our malleable iron threaded fittings spec sheet.